> Even if GCC had very clean separation between the steps, the FSF's interpretation is that you couldn't use the GCC parser for something like highlighting/sugg

> Even if GCC had very clean separation between the steps, the FSF's interpretation is that you couldn't use the GCC parser for something like highlighting/suggestions the way Apple does in XCode without making all of XCode GPL. Only in this one technical implementation you've imagined. Interacting with GPLd tools via basically any method expect actually linking it into your code (e.g. pipes) doesn't infect your code with GPL obligations. Presumably just piping the entire code to gcc -fdump-tree-original every keystroke would be too slow but you could probably get it working nicely if you had the sort of engineer time Apple do.